Hydroseeding is well known and consists of mixing seeds, water, and a substrate into a slurry and spreading the slurry over an exposed area of soil. The substrate provides a cover mat to the soil, holding moisture in while reducing sunlight on the soil, thereby preventing weed seeds in the soil from sprouting. Often, fertilizer, minerals, dyes and/or tacking agents, etc, are added to the slurry to improve germination, moisture retention and growth.
Hydroseeding is an improvement over traditional soil preparation and broadcast seeding since it promotes quick germination and provides mulch to reduce soil erosion. Hydroseeding is a lower cost alternative to sod, requiring less preparation, less transportation costs, lower material costs, less labor and faster deployment.
Hydroseeding is also referred to as hydraulic mulch seeding, hydro-mulching or hydra-seeding, and is performed by pressurizing a tank of slurry and spraying the slurry evenly over the exposed soil. Hydroseeding is usually performed using a truck specifically designed for Hydroseeding and the truck usually has a tank, air compressor for pressurizing the tank, a hose to transport the slurry from the truck and a nozzle that forms a spray of slurry under an operator control. Given such a device, a single operator is capable of seeding a very large area in a matter of minutes. Hydroseeding has also been performed from low-flying aircraft in areas that are without any road infrastructure such as forests, in particular, after a forest fire. In such, it is anticipated that Hydroseeding is performed without seed (e.g., a slurry of a substrate, minerals, fertilizer and water) to re-grow an area of the forest without introducing non-native plant species.
Hydroseeding is also used to seed areas with other plant seeds such as wildflower seeds or combinations of grass seed and other plant seeds.
When introduced in the early 1950s, shredded and ground newspaper was often used as the substrate. Later, more advanced substrate formulas were deployed including components such as paper, wood fibers and polymers. For example, U.S. Pat. No. 6,158,167 to Spittle describes mulch flakes made from finely divided paper and/or wood with added surfactants. This patent claims that, once sprayed on the ground, these flakes reduce water run-off and soil erosion.
Current substrates typically are made from grinding wood fiber (100%) or a mixture of wood fiber and newspaper (e.g., 70% wood fiber and 30% newspaper) and adding dye and surfactants.
What is needed is a substrate that will improve water absorbency while maintaining a homogenous viscosity of the slurry.